Bone grafting and compaction

ABSTRACT

A tool for delivery and/or compaction of bone graft material includes a cannula with an inner lumen extending along a longitudinal axis from a hopper end of the cannula to a delivery tip of the cannula. A hopper with an internal volume for storing bone graft material is connected to the hopper end of the cannula with the internal volume of the hopper in communication with the inner lumen of the cannula for delivery of bone graft material from the hopper to the delivery tip of the cannula. An output shaft within the inner lumen extends along the longitudinal axis. The output shaft includes a helical screw thread extending radially outward from the output shaft toward an inner surface of the cannula. An actuator is connected to the hopper and to the output shaft to drive the output shaft rotationally relative to the hopper and to the cannula.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to U.S.patent application Ser. No. 16/163,102 filed Oct. 17, 2018, which claimspriority to U.S. Provisional Patent Application No. 62/573,856, filedOct. 18, 2017, the contents of which are incorporated herein in theirentirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to bone grafting and compaction, and moreparticularly to tools and methods for bone grafting and compaction.

2. Description of Related Art

There are many orthopedic applications where bone grafting is necessary.Bone grafts generally fall into different categories based on the sourceof the bone graft material. An autograft utilizes bone from a patient'sown body and is often harvested from the patient's iliac crest. Anallograft utilizes bone tissue from someone other than the patient, andcan be harvested from a cadaver. Often allograft material is provided assmall pellets that are planted in a patent where bone growth is needed.In addition to autograft and allograft, there are synthetic variants.

During a surgical operation that involves bone grafting, the bone graftmaterial must be delivered to the site where bone growth is needed. Oncein place, the bone graft material typically needs to be compacted toensure proper integration. The delivery and compaction of bone graftmaterial can be complicated where the bone graft site is small and/orthe procedure is minimally invasive. For example, delivery andcompaction of bone graft material for procedures on spinal arch pediclescan be difficult using traditional techniques.

The conventional techniques have been considered satisfactory for theirintended purpose. However, there is an ever present need for improveddelivery and compaction of bone graft material. This disclosure providesa solution for this need.

SUMMARY OF THE INVENTION

A tool for delivery and/or compaction of bone graft material includes acannula with an inner lumen extending along a longitudinal axis from ahopper end of the cannula to a delivery tip of the cannula. A hopperwith an internal volume for storing bone graft material is connected tothe hopper end of the cannula with the internal volume of the hopper incommunication with the inner lumen of the cannula for delivery of bonegraft material from the hopper to the delivery tip of the cannula. Anoutput shaft within the inner lumen extends along the longitudinal axis.The output shaft includes a helical screw thread extending radiallyoutward from the output shaft toward an inner surface of the cannula. Anactuator is connected to the hopper and to the output shaft to drive theoutput shaft rotationally relative to the hopper and to the cannula.

The actuator can be configured to withdraw the output shaft axiallyalong the longitudinal axis in a direction into the hopper whilerotating the output shaft for engaging bone graft material with thehelical screw thread in the hopper. The actuator can be configured toextend the output shaft axially along the longitudinal axis in adirection out of the hopper for pushing bone graft material engaged withthe helical screw thread out of the hopper and out of the inner lumen ofthe cannula. The actuator can be configured to extend the output shaftaxially along the longitudinal axis in a direction out of the hopperwithout rotating the output shaft for at least part of a stroke. Theactuator can be configured to convert reciprocating linear inputmovement into motion of the output shaft that alternates between linearmotion extending along the longitudinal axis to push bone graft materialout of the inner lumen of the cannula and combined linear and rotarymotion withdrawing in a direction toward the internal volume of thehopper so that continued reciprocating linear input movement repeatedlymoves bone graft material from the hopper to the delivery tip of thecannula.

A paddle can extend radially outward from the output shaft within theinternal volume of the hopper for agitating bone graft material withinthe hopper upon rotation of the output shaft. The paddle can be proximalof the helical screw thread.

The actuator can include a bottom cam mounted stationary relative to thehopper. A driver can be engaged for sliding linear motion relative tothe bottom cam. A top cam can be mounted stationary relative to thehopper. The output shaft can include at least one cam followerconfigured to alternately cam with the bottom cam and with the top camto convert reciprocating linear input movement of the driver into motionof the output shaft that alternates between linear motion extendingalong the longitudinal axis to push bone graft material out of the innerlumen of the cannula and combined linear and rotary motion withdrawingin a direction toward the internal volume of the hopper so thatcontinued reciprocating linear input movement of the driver repeatedlymoves bone graft material from the hopper to the delivery tip of thecannula.

A biasing member can be mounted to bias the output shaft in a directiontoward the delivery tip of the cannula, wherein biasing force of thebiasing member must be overcome to move the driver and output shaft in adirection away from the delivery tip of the cannula. The top cam caninclude at least one camming surface configured to rotate the outputshaft as the driver presses the at least one cam follower of the driveshaft into the at least one camming surface of the top cam. The bottomcam can include at least one camming surface configured to rotate theoutput shaft as the output shaft is biased toward the delivery tip ofthe cannula to rotationally position the output shaft for a subsequentcamming against the top cam.

A method of delivering bone graft material to a bone graft site includeswithdrawing a portion of an output shaft into a hopper housing bonegraft material to engage the bone graft material in the hopper. Themethod also includes pushing the portion of the output shaft axially outof the hopper to deliver bone graft material from the hopper to a bonegraft site.

The output shaft can include a helical screw thread, and withdrawing theportion of the output shaft into the hopper can include withdrawing thehelical screw thread helically by combined linear and rotary motion.Helically withdrawing can include driving the output shaft with helicalmotion that follows the helical screw thread to keep in place bone graftmaterial in a cannula housing at least a portion of the helical screwthread. The cannula can be connected at one end to a hopper and caninclude a delivery tip at an end opposite the hopper, wherein deliveringbone graft material from the hopper to a bone graft site includesejecting bone graft material from the delivery tip of the cannula to abone graft site. The method can include compacting bone graft materialinto the bone graft site using applied pressure from at least one of thecannula, the helical screw thread, and/or the output shaft.

Withdrawing the portion of the output shaft, pushing the portion of theoutput shaft, delivering bone graft material, and compacting bone graftmaterial into the bone graft site can be repeated. Repeatedlywithdrawing the portion of the output shaft, pushing the portion of theoutput shaft, delivering bone graft, and compacting bone graft materialinto the bone graft site can be driven by reciprocating linear motion ofan actuator operatively connected to the output shaft.

The method can include agitating the bone graft material within thehopper using rotary motion of at least one paddle extending radiallyfrom the output shaft. The method can include compacting bone graftmaterial from the hopper into at least two different bone graft siteswith a single bone graft delivery tool comprising the hopper and theoutput shaft.

The method can include expanding an intervertebral body in situ, whereindelivering bone graft material from the hopper to a bone graft siteincludes delivering bone graft material to an interior space of theintervertebral body after expanding the intervertebral body in situ. Itis also contemplated that delivering bone graft material from the hopperto a bone graft site includes delivering bone graft material to aproximal femur during a hip revision procedure, or to any other suitablesite during any other suitable procedure.

These and other features of the systems and methods of the subjectdisclosure will become more readily apparent to those skilled in the artfrom the following detailed description of the preferred embodimentstaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosureappertains will readily understand how to make and use the devices andmethods of the subject disclosure without undue experimentation,preferred embodiments thereof will be described in detail herein belowwith reference to certain figures, wherein:

FIG. 1 is a perspective view of an exemplary embodiment of a tool fordelivery and/or compaction of bone graft material constructed inaccordance with the present disclosure, showing the actuator connectedto the hopper and the output shaft in the cannula;

FIG. 2 is a partially cross-sectional perspective view of the tool ofFIG. 1 , showing the output shaft;

FIG. 3 is a an exploded perspective view of the tool of FIG. 1 , showingthe top cam, bottom cam, and driver of the actuator separated from oneanother;

FIG. 4 is schematic a perspective view of the actuator of FIG. 3 ,showing a first stage in actuating the tool, wherein the top cam isshown as though transparent to reveal underlying structures;

FIG. 5 is a schematic perspective view of the actuator of FIG. 4 ,showing the driver moving axially upward to drive the cam followers ofthe output shaft into the camming surfaces of the top cam;

FIG. 6 is a schematic perspective view of the actuator of FIG. 4 ,showing the end of the upward motion of the driver;

FIG. 7 is a schematic perspective view of the actuator of FIG. 4 ,showing downward movement of the output shaft;

FIG. 8 is a schematic perspective view of the actuator of FIG. 4 ,showing the end of the downward movement of the output shaft;

FIG. 9 is a schematic perspective view of the actuator of FIG. 4 ,showing the downward movement of the driver to return the actuator tothe state of FIG. 4 ;

FIG. 10 is a partially cross-sectional side elevation view of a portionof the tool of FIG. 1 , showing the output shaft position correspondingto the actuator position of FIG. 4 ;

FIG. 11 is a partially cross-sectional side elevation view of a portionof the tool of FIG. 1 , schematically showing the output shaft windingupward corresponding to the actuator positions in FIGS. 5-6 ;

FIG. 12 is a partially cross-sectional side elevation view of a portionof the tool of FIG. 1 , schematically showing the output shaft extendingaxially corresponding to the actuator position shown in FIG. 7 ;

FIG. 13 is a partially cross-sectional side elevation view of a portionof the tool of FIG. 1 , schematically showing a small helical indexingmotion of the output shaft corresponding to the actuator positions shownin FIGS. 8 and 9 ;

FIG. 14 is a schematic view of a method in accordance with the presentinvention, indicating delivery of bone graft material to a proximal hipduring a hip revision procedure;

FIG. 15 is a schematic view of an interbody device in an unexpandedstate;

FIG. 16 is a schematic view of the interbody device of FIG. 15 in anexpanded state;

FIG. 17 is a schematic view of a method in accordance with the presentinvention, showing the interbody device of FIG. 16 with a tool of FIG. 1delivering bone graft material to the inside of the interbody device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like referencenumerals identify similar structural features or aspects of the subjectdisclosure. For purposes of explanation and illustration, and notlimitation, a partial view of an exemplary embodiment of a tool fordelivery and/or compaction of bone graft material in accordance with thedisclosure is shown in FIGS. 1-2 and is designated generally byreference character 100. Other embodiments of tools in accordance withthe disclosure, or aspects thereof, are provided in FIGS. 3-17 , as willbe described. The systems and methods described herein can be used todeliver and compact bone graft material in bone graft sites fororthopedic procedures, e.g., to improve bone screw fixation such as inpedicle screw fixation for spinal procedures.

A tool 100 for delivery and compaction of bone graft material includes acannula 102 with an inner lumen 104 extending along a longitudinal axisA from a hopper end 106 of the cannula 102 to a delivery tip 108 of thecannula 102. Longitudinal axis A is labeled with proximal and distaldirections in FIGS. 1-3 , wherein the proximal and distal directions arereferenced with respect to a user such as a surgeon operating the tool100. A hopper 110 with an internal volume for storing bone graftmaterial, indicated schematically in FIG. 2 , is connected to the hopperend 106 of the cannula 102 with the internal volume of the hopper 110 incommunication with the inner lumen 104 of the cannula 102 for deliveryof bone graft material from the hopper 110 out through the delivery tip108 of the cannula 102.

An output shaft 112 within the inner lumen 104 extends along thelongitudinal axis A. As shown in FIG. 3 , output shaft 112 can beseparated into a proximal section and a distal section, but thoseskilled in the art will readily appreciate that output shaft 112 can bemade as a single unitary piece without departing from the scope of thisdisclosure. The output shaft 112 includes a helical screw thread 114extending radially outward from the output shaft 112 toward an innersurface of the cannula 102. A pair of diametrically opposed paddles 116extends radially outward from the output shaft 112 within the internalvolume of the hopper 110 for agitating bone graft material within thehopper 110 upon rotation of the output shaft 112. The paddles 116 areproximal of the helical screw thread 114.

An actuator 118 is connected to the hopper 110 and to the output shaft112 to drive the output shaft 112 rotationally relative to the hopper110 and cannula 102. The actuator 118 includes a bottom cam 120 mountedstationary relative to the hopper 110. A driver 122 is engaged forsliding linear motion relative to the bottom cam 120 along thelongitudinal axis A. A top cam 124 is mounted stationary relative to thehopper 110. The output shaft 112 includes a set of cam followers 126configured to alternately cam with the bottom cam 120 and with the topcam 124 to convert reciprocating linear input movement of the driver 122into motion of the output shaft 112 that alternates between linearmotion extending distally along the longitudinal axis A to push bonegraft material out of the inner lumen 104 of the cannula 102 andcombined linear and rotary motion withdrawing in a proximal directiontoward the internal volume of the hopper 110. As will be explained infurther detail below, continued reciprocating linear input movement ofthe driver 122 repeatedly moves bone graft material from the hopper 110to the delivery tip 108 of the cannula 102.

A biasing member 128 is mounted, e.g., with one end stationary withintop cam 124, to bias the output shaft 112 in a distal direction towardthe delivery tip 108 of the cannula 102. The biasing force of thebiasing member 108 must be overcome to move the driver 122 and outputshaft 112 in a proximal direction away from the delivery tip 108 of thecannula 102.

The top cam 124 includes a set of camming surfaces 130, identified inFIGS. 4-9 , configured to rotate the output shaft 112 as the driver 122presses the cam followers 126 of the drive shaft 112 into the respectivecamming surfaces 130 of the top cam 124. The bottom cam 120 includes aset of camming surfaces 132, identified in FIGS. 3 and 4-9 , configuredto rotate the output shaft 112, in the same direction as the cammingsurfaces 130 rotate the output shaft 112, as the output shaft 112 isbiased toward the delivery tip 108 of the cannula 102 to rotationallyposition the output shaft 112 for a subsequent camming against thecamming surfaces 130 of the top cam 124.

With reference now to FIGS. 10-11 , a method of delivering bone graftmaterial to a bone graft site includes starting from the output shaftposition shown in FIG. 10 and withdrawing a portion of the output shaft112 into the hopper 110 housing bone graft material (bone graft materialis not shown in FIG. 10 , but see FIG. 2 ) as shown in FIG. 11 to engagethe bone graft material in the hopper 110. Withdrawing the portion ofthe output shaft 112 into the hopper 110 includes withdrawing thehelical screw thread 114 helically by combined linear and rotary motionrelative to longitudinal axis A as indicated schematically in FIG. 11 bythe large axial and circumferential arrows. This helical motion followsthe helical screw thread 114 to keep in place bone graft material in acannula 102 that houses at least a portion of the helical screw thread114.

Referring now to FIG. 12 , the method also includes pushing the portionof the output shaft 112 axially out of the hopper 110 to deliver bonegraft material from the hopper 110 to a bone graft site, pushing bonegraft material engaged with the helical screw thread 114 out of thehopper 110 and out of the inner lumen 104 of the cannula 102. For atleast part of this outward stroke, the actuator 118 is configured toextend the output shaft 112 axially along the longitudinal axis A in adirection out of the hopper 110 without rotating the output shaft 112.The large arrow in FIG. 12 schematically indicates this axial movement.As the large diagonal arrow in FIG. 13 indicates, the extension motionof the output shaft 112 and the helical screw thread 114 of FIG. 12completes with a small helical indexing motion at the end of the outwardstroke of the output shaft 112. This resets the cam followers 126 for asubsequent cycle of camming with the camming surfaces 130 of the top cam124 (the cam followers 126 and camming surfaces 130 are shown in FIGS.4-9 ). The method includes agitating the bone graft material within thehopper 110 using rotary motion of the paddles 116 extending radiallyfrom the output shaft 112 to facilitate loading bone graft material intothe inner lumen 104 of the cannula 102. The rotary motion of the paddles116 is demonstrated by comparing the positions of the paddles 116 inFIGS. 10-13 .

The axial movement in FIG. 12 of the output shaft 112 and its helicalscrew thread 114 pushes or ejects bone graft material out of the innerlumen 104 at the delivery tip 108 of the cannula 102 and allows asurgeon to deliver and even compact bone graft material into a bonegraft site, e.g. starting at the bottom of a hole in a bone, such aswhen using bone graft material in a hole in a spinal arch pedicle toimprove bone screw fixation. For example, this can improve sacral orspinal pedicle screw fixation in osteoporotic applications. FIG. 17shows a pedicle screw 204 for reference. Compacting bone graft materialinto the bone graft site is possible by applying pressure from at leastone of the cannula 102, the helical screw thread 114, and/or the outputshaft 112. Tool 100 enables a surgeon to deliver and compact bone graftmaterial from the hopper 110 into at least two different bone graftsites with a single bone graft delivery tool 100 during a singlesurgical procedure.

With reference again to FIG. 4 , the actuator 118 converts reciprocatinglinear input movement on the driver 122 in the axial direction alonglongitudinal axis A into motion of the output shaft 112 that alternatesbetween the linear extending motion along the longitudinal axis A andthe helical withdrawing motion described above so that continuedreciprocating linear input movement of the driver 122 repeatedly movesbone graft material from the hopper 110 to the delivery tip 108 of thecannula 102. From the initial position shown in FIG. 4 , whichcorresponds to the position of the output shaft 112 shown in FIG. 10 ,the driver 122 moves upward or proximal as indicated by the large arrowin FIG. 5 . This upward motion in the axial direction pushes the outputshaft 112 proximally, its cam followers 126 forced upward by the arms134 of the driver 122, driving the cam followers 126 into rotationalcamming against the camming surfaces 130 of the top cam 124. Thisproximal axial motion ends in the position shown in FIG. 6 , asindicated by the large arrow in FIG. 6 . The actuator positions of FIGS.5 and 6 correspond to the motion of output shaft 112 indicated in FIG.11 . The biasing force from the biasing member 128 (not shown in FIGS.4-9 , but see FIGS. 1-3 ) pushes the output shaft 112 downward as shownin FIG. 7 , flexing the arms 134 of the driver radially outward so thecam followers 126 can pass downward past the arms 134. The actuatorposition of FIG. 7 corresponds to the position of the output shaft 112shown in FIG. 12 .

As shown in FIG. 8 , the cam followers 126 bottom out on the respectivecamming surfaces 132 of the bottom cam 120. As the biasing member 128continues to drive the output shaft 112 downward, the camming surfaces132 cause the small helical movement at the end of the downward stroketo reset the position of the cam followers 126 for the next upwardmovement, where the cam followers 126 come to rest against respectiveshelves 136 of the bottom cam 120. The shelves 136 are identified inFIG. 3 . Finally, the driver 122 can be returned to its initial positionas indicated schematically by the large arrow in FIG. 9 . From here, thenext reciprocating linear movement of the driver 122 can be initiatedbeginning again from the position shown in FIG. 4 . The actuatorpositions of FIGS. 8 and 9 correspond to the motion of the output shaftindicated in FIG. 13 . Impacting the bone graft material after it isdelivered to the bone graft site can allow it to be impacted for betterpurchase of bone screws, densifying the bone where a bone screw is to befixated.

Tools and methods as described herein facilitate tamping bone graftmaterial in place in difficult to reach places, such as during minimallyinvasive surgery. For example, in lumbar interbody fusion (LIF), anintervertebral body 200 can be delivered to the intervertebral space inan unexpanded state, shown in FIG. 15 , in a minimally invasiveprocedure. Once in place, the intervertebral body can be expanded asshown in FIG. 16 , and tool 100 as disclosed herein can be used todeliver bone graft material to the interior space 202 of the expandedintervertebral body, as indicated in FIG. 17 . Those skilled in the artwill readily appreciate that this can be accomplished using an anteriorapproach (ALIF), or any other approach such as posterior (PLIF),transforaminal (TLIF) or extreme lateral (XLIF). While described withexamples relating to spinal and sacral procedures, those skilled in theart will readily appreciate that tools and methods as described hereincan readily be applied to any suitable orthopedic application withoutdeparting from the scope of this disclosure. For example, in revisionhips, bone graft material can be impacted into the proximal femur 190using tools and methods described herein to improve fixation, asindicated schematically in FIG. 14 . Any suitable bone graft materialcan be used in conjunction with tools and methods as described hereinincluding calcium sulfate, autograft, allograft, bone graft protein, orthe like, without departing from the scope of this disclosure.

The methods and systems of the present disclosure, as described aboveand shown in the drawings, provide for delivery and compaction of bonegraft material with superior properties including ease of use and theability to deliver and compact bone graft material to multiple bonegraft sites using a single tool in a given surgery. While the apparatusand methods of the subject disclosure have been shown and described withreference to preferred embodiments, those skilled in the art willreadily appreciate that changes and/or modifications may be made theretowithout departing from the scope of the subject disclosure.

What is claimed is:
 1. A tool for delivery and/or compaction of bonegraft material comprising: a cannula with an inner lumen extending alonga longitudinal axis from a hopper end of the cannula to a delivery tipof the cannula; a hopper with an internal volume for storing bone graftmaterial, wherein the hopper is connected to the hopper end of thecannula with the internal volume of the hopper in communication with theinner lumen of the cannula for delivery of bone graft material from thehopper to the delivery tip of the cannula; an output shaft within theinner lumen extending along the longitudinal axis, the output shaftincluding a helical screw thread extending radially outward from theoutput shaft toward an inner surface of the cannula; and an actuatorconnected to the hopper and to the output shaft to drive the outputshaft rotationally relative to the hopper and to the cannula, whereinthe actuator is configured to drive motion of the output shaft thatalternates between a first stroke motion including linear motionextending along the longitudinal axis to push bone graft material out ofthe inner lumen of the cannula and a second stroke motion includingcombined linear and rotary motion withdrawing in a direction toward theinternal volume of the hopper so that continued alternating between thefirst stroke motion and the second stroke motion repeatedly moves bonegraft material from the hopper to the delivery tip of the cannula. 2.The tool as recited in claim 1, wherein in the second stroke motion theactuator is configured to withdraw the output shaft axially along thelongitudinal axis in a direction into the hopper while rotating theoutput shaft for engaging bone graft material with the helical screwthread in the hopper.
 3. The tool as recited in claim 1, wherein in thefirst strike motion the actuator is configured to extend the outputshaft axially along the longitudinal axis in a direction out of thehopper for pushing bone graft material engaged with the helical screwthread out of the hopper and out of the inner lumen of the cannula. 4.The tool as recited in claim 1, wherein the actuator is configured toconvert reciprocating linear input movement into motion of the outputshaft that alternates between linear motion extending along thelongitudinal axis to push bone graft material out of the inner lumen ofthe cannula and combined linear and rotary motion withdrawing in adirection toward the internal volume of the hopper the first and secondstroke motions so that continued reciprocating linear input movementrepeatedly moves bone graft material from the hopper to the delivery tipof the cannula.
 5. The tool as recited in claim 1, further comprising apaddle extending radially outward from the output shaft within theinternal volume of the hopper for agitating bone graft material withinthe hopper upon rotation of the output shaft.
 6. The tool as recited inclaim 5, wherein the paddle is proximal of the helical screw thread. 7.The tool as recited in claim 1, wherein the actuator includes: a bottomcam mounted stationary relative to the hopper; a driver engaged forsliding linear motion relative to the bottom cam; and a top cam mountedstationary relative to the hopper, wherein the output shaft includes atleast one cam follower configured to alternately cam with the bottom camand with the top cam to convert reciprocating linear input movement ofthe driver into motion of the output shaft that alternates betweenlinear motion extending along the longitudinal axis to push bone graftmaterial out of the inner lumen of the cannula and combined linear androtary motion withdrawing in a direction toward the internal volume ofthe hopper so that continued reciprocating linear input movement of thedriver repeatedly moves bone graft material from the hopper to thedelivery tip of the cannula.
 8. The tool as recited in claim 7, furthercomprising a biasing member mounted to bias the output shaft in adirection toward the delivery tip of the cannula, wherein biasing forceof the biasing member must be overcome to move the driver and outputshaft in a direction away from the delivery tip of the cannula.
 9. Thetool as recited in claim 7, wherein the top cam includes at least onecamming surface configured to rotate the output shaft as the driverpresses the at least one cam follower of the drive output shaft into theat least one camming surface of the top cam.
 10. The tool as recited inclaim 7, wherein the bottom cam includes at least one camming surfaceconfigured to rotate the output shaft as the output shaft is biasedtoward the delivery tip of the cannula to rotationally position theoutput shaft for a subsequent camming against the top cam.
 11. A toolfor delivery and/or compaction of bone graft material comprising: acannula with an inner lumen extending along a longitudinal axis from ahopper end of the cannula to a delivery tip of the cannula; a hopperwith an internal volume for storing bone graft material, wherein thehopper is connected to the hopper end of the cannula with the internalvolume of the hopper in communication with the inner lumen of thecannula for delivery of bone graft material from the hopper to thedelivery tip of the cannula; an output shaft within the inner lumenextending along the longitudinal axis, the output shaft including ahelical screw thread extending radially outward from the output shafttoward an inner surface of the cannula; an actuator connected to thehopper and to the output shaft to drive the output shaft rotationallyrelative to the hopper and to the cannula; and a paddle extendingradially outward from the output shaft within the internal volume of thehopper for agitating bone graft material within the hopper upon rotationof the output shaft; wherein the actuator is configured to drive motionof the output shaft that alternates between a first stroke motionincluding linear motion extending along the longitudinal axis to pushbone graft material out of the inner lumen of the cannula and a secondstroke motion including combined linear and rotary motion withdrawing ina direction toward the internal volume of the hopper so that continuedalternating between the first stroke motion and the second stroke motionrepeatedly moves bone graft material from the hopper to the delivery tipof the cannula.
 12. The tool as recited in claim 11, wherein in thesecond stroke motion the actuator is configured to withdraw the outputshaft axially along the longitudinal axis in a direction into the hopperwhile rotating the output shaft for engaging bone graft material withthe helical screw thread in the hopper.
 13. The tool as recited in claim11, wherein in the first strike motion the actuator is configured toextend the output shaft axially along the longitudinal axis in adirection out of the hopper for pushing bone graft material engaged withthe helical screw thread out of the hopper and out of the inner lumen ofthe cannula.
 14. The tool as recited in claim 11, wherein the actuatoris configured to convert reciprocating linear input movement into motionof the output shaft that alternates between linear motion extendingalong the longitudinal axis to push bone graft material out of the innerlumen of the cannula and combined linear and rotary motion withdrawingin a direction toward the internal volume of the hopper the first andsecond stroke motions so that continued reciprocating linear inputmovement repeatedly moves bone graft material from the hopper to thedelivery tip of the cannula.
 15. The tool as recited in claim 11,wherein the paddle is proximal of the helical screw thread.
 16. The toolas recited in claim 11, wherein the actuator includes: a bottom cammounted stationary relative to the hopper; a driver engaged for slidinglinear motion relative to the bottom cam; and a top cam mountedstationary relative to the hopper, wherein the output shaft includes atleast one cam follower configured to alternately cam with the bottom camand with the top cam to convert reciprocating linear input movement ofthe driver into motion of the output shaft that alternates betweenlinear motion extending along the longitudinal axis to push bone graftmaterial out of the inner lumen of the cannula and combined linear androtary motion withdrawing in a direction toward the internal volume ofthe hopper so that continued reciprocating linear input movement of thedriver repeatedly moves bone graft material from the hopper to thedelivery tip of the cannula.
 17. The tool as recited in claim 16,further comprising a biasing member mounted to bias the output shaft ina direction toward the delivery tip of the cannula, wherein biasingforce of the biasing member must be overcome to move the driver andoutput shaft in a direction away from the delivery tip of the cannula.18. The tool as recited in claim 16, wherein the top cam includes atleast one camming surface configured to rotate the output shaft as thedriver presses the at least one cam follower of the drive output shaftinto the at least one camming surface of the top cam.
 19. The tool asrecited in claim 16, wherein the bottom cam includes at least onecamming surface configured to rotate the output shaft as the outputshaft is biased toward the delivery tip of the cannula to rotationallyposition the output shaft for a subsequent camming against the top cam.20. A tool for delivery and/or compaction of bone graft materialcomprising: a cannula with an inner lumen extending along a longitudinalaxis from a proximal end toward a distal end; a hopper with an internalvolume, the hopper positioned at the proximal end of the cannula; anoutput shaft positioned within the inner lumen of the cannula andextending along the longitudinal axis, the output shaft including ahelical screw thread extending radially outward from the output shaft;and an actuator mechanically coupled to the output shaft, wherein theactuator is configured to, in a first motion, advance the output shaftdistally through the cannula without rotating the output shaft and, in asecond motion, pull the output shaft proximally through the cannulawhile simultaneously rotating the output shaft.